1. Field of the Invention
The invention relates to a fiber for producing three-dimensional, self-interlacing composites.
2. Description of the Related Art
The reinforcing elements of most lightweight composites are high tensile strength fibers of compounds or polymers, such as fiberglass or carbon fiber or other suitable reinforcing fibers used in composites. Woven or unwoven, those layers of fibers are limited to two-dimensional interlacements. The fiber “becomes the strength” of the finished composite, and are layered into pre-made forms or molds and hardened into desired shapes by hardening binders. Different fiber patterns, fiber “tape” or even sprayed, non-interlacing short fibers fail to improve the fiber integrity. Two-dimensional orientations of the fibers give superb strength in the single plane of the XY (east-west and north-south) axis, due to crisscrossing, interlacing, or interlocking of fibers, which create “in effect” a continuous and locked fiber. Since no effective fibers run between the layers, to complete a true “vertical” interlocking in the third dimension, those materials have a much reduced strength in this Z (front to back) axis. It is only in flat or gently curving forms like boats or tubes, where the material can be formed with good overlap, minimal distortion or cutting of the fibers and where stresses can be restricted to the two dimensions or “in plane” with the directions of interlacements, that the strength of the composite is preserved. The fibers' own rigidity restricts stretching and makes layering in irregular or hyper-contoured molds very difficult. To fold, distort or cut the remaining interlinking or to use chopped fibers which have zero interlinking is so destructive to strength integrity as to make the techniques unwise.
A contoured composite object, formed with destroyed XY axis strength (no interlinking) and no Z axis strength (no interlinking) has little tensile strength in any direction, and failures or delaminations occur because there are no remaining effective strength elements, just a “weak glued-together mixture”. The integrity of the fiber continuity is everything in composites because the hardening binders carry no significant portion of the stress loads.